With regard to standing structure, it may be required to install any or all of a moisture barrier, a sound or thermal insulation or fire rated board much as fire rated gypsum board.
One current problem with respect to such structures, characterized as being potentially disastrous to the home building industry and requiring billions of dollars to correct (Professional Builder, Technology, June 1990, pp. 80, 90, and The Evening Sun, Newspaper, Baltimore, Section A, March 28, 1990), is that much of fireretardant treated board chemically alters and deteriorates to the extent that whole roofs must be replaced.
Prior art devices adaptable for installations of the type are not uniformly cost efficient in fabrication, simplicity of assembly and completeness of structural area coverage.
In this connection, see the U.S. Pat. Nos. 2,999,277 and 2,999,278--Spencer et al.; U.S. Pat. No. 4,346,544 Larssen and West German Patents 2,315,793--Oct. 3, 1974, and 2,340,309--Feb. 20, 1975.